The present invention relates to a haptic solenoid that provides haptic feedback and is used, for example, in touch input devices.
A haptic solenoid is described, for example, in Japanese Patent Laid-Open Publication No. 2010-27613 which, as shown in FIG. 5, comprises a plastic frame 101 having a central open area; a fixed pole 102, which is fixed to a lower long leg 101A and an upper long leg 101B of the plastic frame 101; a mobile pole 103; and a coil 104, which is mounted on the fixed pole 102.
With this haptic solenoid, when the current to the coil is turned ON and OFF, the mobile pole 103 is attracted to and distanced from the fixed pole 102, which produces an elastic deformation in a side piece 101C between the lower long leg 101A and the upper long leg 101B, so as to vibrate a touchscreen frame (vibrated body) that is coupled to the upper long leg 101B, but which is not shown in the drawing.
In the haptic solenoid described above, the movement of the mobile pole 103 is controlled by way of the magnetic attraction of the fixed pole 102 and the elastic force of the side piece 101C, which is part of the plastic frame 101.
However, there is a tendency for the elastic modulus of the side piece 101C, which is made from plastic, to vary by a relatively large amount depending on the ambient temperature, and consequently there was a possibility of failing to achieve good haptic feedback because, depending on the ambient temperature, the prescribed level of vibration was not achieved.
Furthermore, because the fixed pole 102 and the mobile pole 103 were supported by the hollow plastic frame, with which the elastically deformed side piece 101C was integrally united, due to torsion and the like in the side piece 101C, the direction of vibration was not stable, and consequently there was a possibility of failing to achieve good haptic feedback because the prescribed level of vibration was not achieved.